FR3072468A1 - DEVICE AND METHOD FOR DETECTING UNAUTHORIZED OBJECTS OR MATERIALS USED BY AN INDIVIDUAL IN A PROTECTED ACCESS AREA - Google Patents

Abstract

The invention relates to a device for detecting unauthorized objects or materials carried by an individual in a protected access area, characterized in that it comprises at least two columns (10, 20) defining between them a channel (30) through which individuals can pass through to be controlled, windings (110, 120) distributed in the two columns (10, 20), adapted to To set up a magnetic field of detection and adapted to detect magnetic field disturbances of detection induced during the passage of an individual by the channel between the two columns, means to Microwaves transmitters / receivers (210, 220) disposed in the two columns (10, 20), and analyzing means (40) adapted to analyze the signals from the receiving windings ( 110, 120) for detecting the presence of a metal object carried by an individual passing through said channel formed between the two c olonnes (10, 20), for analyzing signals from microwave receivers (210Rx, 220Rx) corresponding to the signals transmitted from a column to the opposite column and to the signals referred to from a column to the same column to detect the presence of electrical material carried by the individual passing through said channel and to establish the spatial correlations existing between the objects meà © metallics and electrical materials detected.

Description

FIELD OF THE INVENTION

The present invention relates to the field of detectors designed for the detection of unauthorized objects or materials in a protected access area.

TECHNOLOGICAL BACKGROUND

It now appears necessary to control with great reliability the attempts to introduce or exit certain products, for example but not exclusively explosive materials, into or out of a sensitive area.

The problem thus posed covers a very wide range of situations, which includes in particular and without limitation the attempt to introduce products into a protected area, such as a store, school, station, public or even private body, or the attempted exit of products outside a defined perimeter, for example in the event of theft in a company or on a protected site.

In particular, metal detector gantries based on inductive coils have been proposed for many years. The general structure and general operation of these devices are well known to those skilled in the art. For the most part, transmitter coils generate a magnetic field and receiver coils detect disturbances in this field due to metallic objects carried by an individual passing through the gantry. Examples of such metal detector gates can be found in the documents EP 1 750 147 and EP 1 892 542.

For several years, body scanners (generally designated by their Anglo-Saxon terminology “body scanner”) have been developed in order to detect weapons, explosives, etc. hidden under the clothing of individuals entering a protected area. All these systems use technologies based on the detection of radiation energies modulated or emitted by the body of the individuals inspected. The radiation energies thus used include X-rays, microwaves, millimeter waves, infrared light, terahertz waves and ultrasound.

An example of a body scanner is described in document EP 2 202 700.

Despite the use of several types of radiation energies and imaging geometries, many body scanners have as a principle the creation of an electronic image of the individual on which the clothing of the individual is transparent. This image is then displayed on a screen and viewed by an operator so that he can determine whether the individual is carrying a target object. For this, the operator, who is trained in the detection of target objects, must be able to determine whether the objects identified by the body scanner correspond to human anatomy, to an authorized object such as a lighter, a handkerchief or parts, or a target object such as a weapon or an explosive.

The applicant has also proposed devices intended to inspect the shoes and the lower part of the legs of individuals, which comprise a frame which comprises a support base formed by a rectangular plate in the form of a step whose flat upper surface comprises a drawing or footprint and a stop intended to accommodate and position a single foot of an individual wearing a shoe, two symmetrical side panels which house detection means, and an information module.

Examples of this device can be found in documents FR 2860631, EP 1574879, FR 2889338 and FR 2911212.

The detection means described in the mentioned documents can be formed from coils for the detection of metals, from sampling means, for example in the form of suction nozzles, for the sampling of vapors or traces of particles, for example of narcotic drugs. or explosives, means of analysis based on nuclear magnetic resonance comprising for example HelmhoItz coils, or else means of analysis of complex impedances or detectors of radioactive radiation.

All these known devices have already rendered great services.

However, it is now necessary to allow even more precise detections.

In particular, there is today the problem of controlling access to places for the general public, such as stadiums and large theaters, where the entry rate must be several hundred people / hour (up to 1000 people / hour ). The functioning of the Body scanner requires the parking for several seconds of each person to allow the reading by the microwave transducers and for the analysis of the signals obtained by the measurement. The throughput that can thus be obtained, although acceptable for example for airport control, is very low and totally insufficient for consumer applications.

SUMMARY OF THE INVENTION

An objective of the invention is therefore to propose new detection means making it possible to improve the detection of target objects capable of being worn by an individual.

An object of the invention is in particular to propose detection means which are effective whatever the place of fixation of a fraudulent object on an individual, more precisely whether it is on the front of the body, the rear of the body, or part of the body, see a combination of these.

Another objective of the invention is to propose a system which allows a reading or examination on the fly of the person to define whether the perimeter of his body is free or whether he is carrying metallic and / or dielectric objects superimposed.

These objectives are achieved according to the invention thanks to a device which comprises:

- at least two columns defining between them a channel through which individuals to be inspected can pass,

windings distributed in the two columns, adapted to emit a magnetic detection field and adapted to detect the disturbances of the magnetic detection field induced during the passage of an individual through the channel between the two columns,

- microwave transmitter / receiver means arranged in the two columns, and

- analysis means suitable for analyzing the signals from the receiver windings to detect the presence of metallic object carried by an individual passing through said channel formed between the two columns, for analyzing signals from microwave receivers corresponding to the signals transmitted from a column to the opposite column and to the signals reflected from a column towards this same column to detect the presence of dielectric material carried by the individual passing through said channel and to establish the existing spatial correlations between metallic objects and dielectric materials detected.

Unlike the body scanners which require the parking of each person to be checked, the system according to the present invention performs an analysis which uses the movement of the person as a “spatial scan” of his perimeter with respect to the columns of the transmitters and inductive and microwave receivers, thereby solving the need for high throughput.

The invention also relates to a method of detecting fraudulent objects carried by an individual using the aforementioned device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics, objects and advantages of the present invention will appear better on reading the detailed description which follows, and with regard to the appended drawings given by way of nonlimiting examples and in which:

FIG. 1 represents a perspective view of a device according to the present invention,

FIG. 2 represents the same device by schematically illustrating the positioning of microwave transmitter / receiver means arranged in the two columns of the device,

FIG. 3 represents a schematic vertical view of microwave beams emitted by the device according to the present invention,

- Figure 4a shows schematically a top view of microwave emissions from a transmitter placed on a column towards a receiver placed on the opposite column and Figure 4b illustrates the signal received on the receiver before qu 'an individual does not intercept the microwave beam,

FIG. 5a represents a similar view when an individual intercepts the microwave beam and FIG. 5b illustrates the signal reflected towards the emitter / receiver transducer,

- Figure 6 shows schematically a top view of the interactions that may exist between the transmitting transducers and the receiving transducers when each transmitting transducer is adapted to transmit towards several receiving transducers and symmetrically each receiving transducer is adapted to receive the beams emitted by several transmitting transducers,

- Figure 7a shows schematically a top view of microwave emissions / receptions in the case of an individual passing through the channel and carrying a fraudulent object on the front, Figure 7b schematically represents the signal transmitted through this object characterized by a specific time delay and attenuation and FIG. 7c represents the signal transmitted in the air between another pair of microwave transducers,

- Figure 8a shows schematically a top view of microwave transmissions / receptions in the case of an individual passing through the channel and carrying on the back a fraudulent object, Figure 8b shows schematically the signal transmitted through this object characterized by a specific time delay and attenuation, while FIG. 8c schematically represents the signal reflected on the individual characterized by a specific time delay,

- Figure 9a shows schematically a top view of microwave emissions / receptions in the case of an individual passing through the channel and carrying on the front, but on one side, a fraudulent object and Figure 9b shows schematically the signal transmitted through this object characterized by a specific time delay and attenuation, while FIG. 9c schematically represents the signal reflected on the individual characterized by a specific time delay and FIG. 9d schematically represents a double reflected echo d '' on the one hand on the fraudulent object and on the other hand on the body of the individual each characterized by a time delay and specific attenuation,

- Figure 10a shows a case similar to Figure 9a, the fraudulent object being carried on the opposite side of the individual and Figures 10b, 10c and 10d respectively represent the transmitted signal, the signal reflected on the individual and the double echo similar to Figures 9b, 9c and 9d,

- Figure 11a shows schematically a top view of microwave emissions / receptions in the case of an individual passing through the channel and carrying a fraudulent object laterally, Figure 11b shows schematically the signal reflected on the individual characterized by a specific time delay and FIG. 11c schematically represents a double echo reflected on the one hand on the fraudulent object and on the other hand on the body of the individual, each characterized by a specific time delay and attenuation,

FIG. 12 schematically represents a flow diagram of a method for determining the spatial correlation between the detection of a metallic object using the coils and a dielectric object using the microwave transducers,

- Figure 13a schematically represents 4 transducers distributed in pairs at the same horizontal level on the two columns, at the rate of a transducer located on the inlet and a transducer located on the outlet of each column, and Figure 13b represents a matrix 4x4 of possible interactions between these 4 transducers depending on whether they are successively transmitting and / or receiving,

FIGS. 14a to 14g represent 7 successive typical stages of an individual's progression in the channel and the corresponding detection matrices on the microwave receiver transducers,

- Figures 15a to 15g represent 7 successive typical stages of an individual's progression in the canal, similar to Figures 14a to 14g, in the case where the individual carries on the front of his body a fraudulent dielectric element and the dies corresponding detection on the receiving microwave transducers,

- Figures 16a to 16g represent the successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to Figures 14a to 14g, in the case where the individual relates to the back of his body a fraudulent dielectric element,

- Figures 17a to 17g represent the successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to Figures 14a to 14g, in the case where the individual relates to the front of his body and on his left side, a fraudulent dielectric element, and

- Figures 18a to 18g represent the successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to Figures 14a to 14g, in the case where the individual relates to the front of his body and on his right side, a fraudulent dielectric element.

DETAILED DESCRIPTION OF AN EMBODIMENT

Is shown in the accompanying figures, in particular in Figure 1, a device according to the present invention comprising two columns 10, 20 defining between them a channel 30 through which can pass individuals I to control.

By way of nonlimiting example, the height of the columns 10, 20 can be between 150 and 200cm, advantageously between 150 and 180cm and the distance between the two columns is advantageously between 70 and 100cm.

As previously indicated, the device according to the present invention comprises windings 110 120 distributed in the two columns. These windings 110, 120 are adapted to emit a magnetic detection field and adapted to detect disturbances of the magnetic detection field induced during the passage of an individual through the channel between the two columns.

Such windings 110, 120 are illustrated in particular in FIGS. 4 to 11. They preferably cover the entire height of the columns 10, 20.

The device according to the present invention also comprises analysis means 40 suitable for analyzing the signals from the HORx and 120Rx receiver coils to detect the presence of metallic object carried by an individual I passing through said channel 30 formed between the two columns 10 , 20.

The windings 110, 120 can be the subject of numerous known embodiments, such as those used today in conventional metal detector gantries. Their operation in itself is also classic.

The structure and operation of the windings 110, 120 will therefore not be described in detail below.

Note however that preferably each winding 110, 120 provided respectively on columns 10 and 20 can be formed by several separate windings whose relative distribution over the height of columns 10 and 20 is adapted to optimize detection and is controlled by the means analysis to transmit alternating inductive fields over a frequency range and respectively receive all of these alternating inductive fields over said frequency range.

These provisions are also known per se and will therefore not be described in more detail below.

Preferably, the metal detector inductive fields generated by the windings 110, 120 are in the frequency range between 70 Hz and 30 kHz,

As also indicated above, the device according to the present invention further comprises means 210, 220 forming microwave transmitter / receiver transducers disposed respectively in the two columns 10, 20.

Thereafter these transducers 210, 220 will be accompanied by the index Tx when they are transmitters and Rx when they are receivers.

Preferably each transducer 201, 220 can successively and alternately be transmitter and / or receiver.

Furthermore, the analysis means 40 are also suitable for analyzing the signals from microwave receivers 210Rx and 220Rx.

More precisely, as indicated above, the analysis means 40 of the device according to the present invention are suitable for analyzing the signals from microwave receivers 210Rx and 220Rx corresponding to the signals transmitted from a column to the opposite column. and to the signals reflected from a column to this same column to detect the presence of dielectric material carried by the individual I passing through said channel and to establish the spatial correlations existing between the metallic objects and the dielectric materials detected.

The term “establish the spatial correlations between the metallic objects and the dielectric materials detected” means that the analysis means 40 are adapted to search whether the signals from microwave receivers 210Rx and 220Rx lead to detect a possible fraudulent object on a part of the body of the individual I which also corresponds in space to a detection of metal resulting from the processing of the signals taken from the receiver coils 110 and 120.

The main steps in the process of determining the spatial correlation between a metallic object using the windings 110, 120 and a dielectric object using the microwave transducers 210, 220 have been illustrated diagrammatically in FIG. 12.

Steps 300 and 304 correspond respectively to the detection of a metallic object using the windings 110, 120 and of a dielectric object using the microwave transducers 210, 220. These steps 300 and 304 loop back on themselves as long as no detection is carried out. If necessary, steps 300 and 304 can be followed by respective display steps when a metallic object is detected using the windings 110, 120, or respectively a dielectric object using the transducers. microwave 210, 220.

When a metallic object is detected in step 300 and a dielectric object is detected in step 304, step 308 of searching for spatial correlation between the metallic object and the dielectric object is operated by the means of analysis 40. That is to say that the means of analysis seek whether the metallic object and the dielectric object are detected on the same part of the body of the individual which passes through the channel 30.

In the event of detection of such a correlation, an alarm and a corresponding display are operated in step 312.

The process is resumed originally after the display step 312.

Similarly, the process is resumed at the origin if the step 308 for searching for spatial correlation does not reveal a correlation.

Likewise, a display suitable for step 310 can be provided when a metallic object and a dielectric object are detected separately, with no spatial correlation between these two objects.

Such a correlation between dielectric material and metal makes it possible to help the personnel who control access by the device to specify a diagnosis on the nature of the fraudulent object carried by the individual and makes it possible to adapt the nature of the operations accordingly. to hire.

The device according to the present invention also comprises display means suitable for displaying the detected alarms.

These display means are preferably adapted to display the height and the right or left side of the channel on which a metallic object and a dielectric object are detected in correlation.

More precisely still, the display means in accordance with the present invention are preferably adapted to display a front and rear type silhouette of the individual passing through the channel, sized in size on the basis of a measurement carried out by detection of reflection of microwave beams, with positioning and indication of the nature of metallic objects and non-metallic dielectric objects detected.

The microwave transmitter / receiver transducers 210, 220 preferably comprise several microwave transducers distributed vertically on each column 10, 20. As shown in FIG. 2, 15 transducers can be provided vertically superimposed with a deviation of the order from 2 to 10cm between two adjacent transducers.

Preferably, each microwave transducer 210, 220 is associated with a focusing horn adapted to control the angular opening of the emission cone of each transducer so that all of the transducers 210, 220 constitute a continuous vertical curtain or at least continuous. Preferably, the vertical distribution of the transducers 210, 220 and their emission and reception lobe are determined so that the microwave beams constitute a continuous curtain at least in the longitudinal median plane of the channel 30.

The transducers 210, 220 preferably operate in a frequency range between 5 and 90 GHz, advantageously between 10 GHz and 30 GHz and very preferably between 12 and 20 GHz.

The different transducers 210, 220 located on a column 10 or 20, for example the fifteen vertically distributed transducers, are located respectively coaxially with a transducer 220, 210 located opposite on the opposite column 20, 10.

Each transducer 210, 220 can, under the control of the analysis means 40, work alternately as a transmitter (or 210Tx, 220Tx) or as a receiver (or 210Tx, 220Tx) or as a transmitter and receiver.

As illustrated in FIG. 3, each transmitter 210Tx, 220Tx is preferably adapted to transmit in the direction of a receiver 220Rx, 210Rx coaxial on the opposite column, as well as in the direction of the transducers adjacent to this opposite coaxial transducer, it is that is, towards the immediately upper transducer and the immediately lower transducer.

Likewise, as also illustrated in FIG. 3, each receiver 210Rx, 220Rx is preferably adapted to receive from a coaxial transmitter 220Tx, 210Tx located on the opposite column, as well as from transducers adjacent to this transmitter transducer opposite coaxial, that is to say from the immediately higher transducer and from the immediately lower transducer.

As seen in FIG. 4a, in the context of the present invention, each column 10, 20 can comprise a single vertical series of microwave transducers 210, 220, for example on the input side of the channel 30. According to the figure 4a, the coils 110, 120 used for detecting metals are located in the center of the columns 10, 20.

However, as illustrated in FIGS. 6 to 11, each column 10, 20 can comprise several vertical series of microwave transducers 210, 220. According to the appended FIGS. 6 to 11 which correspond to a non-limiting illustration, it is thus provided coils 110, 120 used for detecting metals in the center of each column 10, 20 and a series of microwave transducers 210, 220 respectively on the input side and on the output side of the coils 110, 120, on each column 10 , 20.

The horizontal distance between two transducers 210, 220 located in the same column is typically between 10 and 30 cm.

As can be seen in FIG. 4b, which corresponds to the situation illustrated in FIG. 4a of an individual I who is preparing to enter the channel 30, when no object or individual is interposed between a transmitter transducer 220Tx and a 210Rx receiver transducer, the 210Rx receiver transducer receives a signal with only a slight delay due to transmission in the air, without significant attenuation in amplitude.

On the other hand as seen in FIG. 5b which corresponds to the situation illustrated in FIG. 5a of an individual who has entered the channel 30 and is situated between a pair of transducers 210, 220, the reception on the receiver transducer Rx is disturbed.

More precisely, as can be seen in FIGS. 5, the microwave beam emitted by a 220Tx transmitter is reflected almost entirely in the direction of the same transducer 220 operating as a 220Rx receiver, due to the density of water in the body of the individual I, with a delay equal to 2 * d / c, d representing the distance between the 220Tx transmitter and the body of the individual I and c representing the speed of microwaves in the air.

The device according to the present invention thus makes it possible, by exploiting the detected reflections, to determine the height height of an individual I who transits through channel 30.

Figures 7 illustrate the operation of the device according to the present invention in the case where the individual I passing through the channel 30 carries a fraudulent object X composed of a substance not permeable to microwaves on the front of his body.

In this case the microwave beam emitted by a transmitting transducer 220Tx in the direction of an opposite receiving transducer 210 Rx is transmitted to the opposite receiving receiver 210 Rx located on the opposite column with a delay and attenuation due to substance X, when object X intercepts the microwave beam as seen in Figure 7b.

In these figures 7 the object X intercepts a microwave beam emitted on the input of the channel.

On the other hand, similarly to FIG. 4b, the object X not being interposed between the transmitter transducer 220Tx and the receiver transducer 210Rx located on the output of channel 30, this receiver transducer 210Rx located on the output of channel 30 receives a signal with only a slight delay due to transmission in the air, without significant amplitude attenuation, as illustrated in Figure 7c.

When the individual I continues to advance in the corridor 30, his body will reflect the microwave beam in the direction of the transmitting transducer as described above with reference to FIGS. 5.

Then the pairs of transducers 210, 220 located at the outlet of the channel 30 will operate, when the individual reaches them, the same detections as the pairs of transducers 210, 220 located at the inlet of the channel 30 have operated when the individual has entered the channel 30.

Figures 8 illustrate the operation of the device according to the present invention in the case where the individual I passing through the channel 30 carries a fraudulent object X composed of a substance not permeable to microwaves on the back of his body.

In this case, firstly the microwave beams emitted by the transducers 210, 220 located at the entrance to the channel 30 are obscured by the individual's body when the latter intercepts the beams (situation comparable to FIGS. 5) .

Then the microwave beam emitted by a transmitter 220Tx transmitter towards an opposite transducer 210 Rx is transmitted to the receiver 210 Rx opposite located on the opposite column with a delay and an attenuation due to the substance X, when the object X intercepts the microwave beam as seen in Figure 8b.

Simultaneously if the longitudinal difference between the two sets of transducers 210 and respectively 220 is small, its body will reflect the microwave beam towards the emitting transducer located at the outlet of the channel 30 as described above with reference to FIGS. 5. The reflected signal corresponding is illustrated in Figure 8c. It is comparable to that of Figure 5b.

On the other hand, similarly to FIG. 4b, the object X not being interposed between the transmitter transducer 220Tx and the receiver transducer 210Rx located on the output of channel 30, this receiver transducer 210Rx located on the output of channel 30 still receives a signal with only a slight delay due to the transmission in the air, without significant attenuation in amplitude, in a manner comparable to FIG. 4b.

When the individual I continues to advance in the corridor 30, the pairs of transducers 210, 220 located at the outlet of the channel 30 will operate, when the individual reaches them, the same detections as the pairs of transducers 210, 220 located at the inlet of the channel 30 operated when the individual entered channel 30.

Figures 9 illustrate the operation of the device according to the present invention in the case where the individual I who transits through the channel 30 carries a fraudulent object X composed of a substance not permeable to microwaves on the front, but of a side of his body.

In this case, firstly the microwave beams emitted between the transducers 210, 220 located at the entrance to the channel 30 are obscured by the body of the individual when the latter intercepts these beams (situation comparable to FIGS. 5; a beam emitted by the input transmitter 220Tx is reflected towards it as illustrated in FIG. 9c with a delay equal to 2 * d / c), but the signal emitted by a transmitter transducer 220Tx located at the output of channel 30 towards a 210Rx receiver transducer located at the input of channel 30 on the side of the object X is transmitted to this 210 Rx receiver with a delay and attenuation due to substance X, when the object X intercepts the micro beam -waves as seen in Figure 9b.

On the other hand, similarly to FIG. 4b, the object X not being interposed between the transmitter transducer 220Tx and the receiver transducer 210Rx located on the output of channel 30, this receiver transducer 210Rx located on the output of channel 30 still receives from the output transmitter transducer 220Tx a signal with only a slight delay due to transmission in the air, without significant attenuation in amplitude, in a manner comparable to FIG. 4b, while the beam emitted by a transducer 210 located at the output towards of the object X is reflected towards this transducer 210 operating as a receiver so that the latter then receives two successive echoes, with different delays: a first echo XI due to the reflection on the substance X and a second echo X2 due to the reflection on the body of individual I, as illustrated in Figure 9d.

When the individual I continues to advance in the corridor 30, the pairs of transducers 210, 220 located at the outlet of the channel 30 will operate, when the individual reaches them, the same detections as the pairs of transducers 210, 220 located at the inlet of the channel 30 operated when the individual entered channel 30.

Figures 10 illustrate the operation of the device according to the present invention in the case where the individual I passing through the channel 30 carries a fraudulent object X composed of a substance not permeable to microwaves on the front, but of a side of his body opposite to the case of FIGS. 9.

The operation of the device is then symmetrical, by a left / right symmetry to that described previously with reference to Figures 9. This operation as well as Figures 10b (reception through substance X received with a delay and attenuation due to substance X ), 10c (reflection by the body and reception on the transmitting transducer with a delay equal to 2 * d / c) and lOd (two successive echoes, with different delays: a first echo XI due to the reflection on substance X and a second echo X2 due to the reflection on the body of the individual I) will therefore not be described in more detail below.

Figures 11 correspond to the case of a fraudulent object X carried laterally by an individual I.

Again the transducers 210, 220 successively detect either a microwave beam substantially without delay and without attenuation when no object or body is interposed between a transmitting transducer and a receiving transducer respectively associated, or a reflection with a delay equal to 2 * d / c when the individual's body is inserted opposite a transmitter, ie two echoes as illustrated in FIG. 11c when the fraudulent object X is placed opposite a transmitter with different delays: a first echo XI due to reflection on substance X and a second echo X2 due to reflection on the body of individual I.

Piloting the transmitter / receiver pairs 210, 220 and the analysis of the signals from an Rx receiver therefore makes it possible to detect the presence on an individual of an object X not permeable to microwaves and makes it possible to give a diagnosis as to the location of this object on the body of individual I.

Generally, according to tests carried out by the inventors, the second echo on the body has a greater amplitude than the first echo on the substance X which is only partially reflective.

Those skilled in the art will understand from reading the above description that the invention thus allows the detection of non-metallic fraudulent substances, for example explosives or drugs, carried by an individual by detection of the delay and of the amplitude of microwave signals transmitted through the substance and / or reflected by the substance, as well as by the body.

The analysis means 40 proceed by comparing the transmitted and / or reflected signals with transmission values in the air and / or signals reflected on a body devoid of fraudulent object.

The means 40 are adapted to generate an alarm when a significant deviation exceeding a threshold is detected with respect to the reference values.

Those skilled in the art will in fact understand that the analysis of the sequences of signals received on the microwave transducers 210, 220 makes it possible to control the progress of an individual in the channel 20, to determine whether this individual is carrying a substance dielectric delay microwaves and determine by analysis of the chronology of the sequences the place of port on the individual.

As indicated previously, FIG. 13a schematically represents 4 transducers 210, 220 distributed in pairs at the same horizontal level on the two columns, on the basis of a transducer situated on the inlet and a transducer situated on the outlet of each column 10, 20 .

Furthermore, FIG. 13b represents a 4x4 matrix of the possible interactions between these 4 transducers according to whether they are successively transmitter and / or receiver.

In FIG. 13b the transducer 210 situated on the left and at the entrance of the channel is referenced 210TxGAv when it is transmitter and 210RxGAv when it is receiver. The transducer 220 located on the right and at the entrance of the channel is referenced 220TxDAv when it is transmitter and 220RxDAv when it is receiver. The transducer 210 located on the left and at the outlet of the channel is referenced 210TxGAr when it is transmitter and 210RxGAr when it is receiver. The transducer 220 located on the right and at the outlet of the channel is referenced 220TxDAr when it is transmitting and 220RxDAr when it is receiving.

Figures 14a to 14g represent 7 successive typical stages of an individual's progression in channel 30 and the corresponding detection matrices on the microwave receiver transducers. In FIGS. 14, "O" is indicated when the receiver does not receive a signal, "Rx" when it receives practically without delay or attenuation the signal coming from the associated transmitter, and "Echo" when it receives its own signal reflected by the body of the individual I,

FIGS. 15a to 15g represent 7 successive typical stages of progression of an individual I in the channel 30, similar to FIGS. 14a to 14g, in the case where the individual carries on the front of his body a fraudulent dielectric element X and the corresponding detection matrices on the receiving microwave transducers. In FIGS. 15, it has been indicated "O" when the receiver does not receive a signal, "Rx" when it receives practically without delay or attenuation the signal coming from the associated transmitter, "Echo" when it receives its own signal reflected by the body of the individual I, and “Attenuated Delay” when it receives a delayed and attenuated signal transmitted through the fraudulent dielectric body X.

Furthermore, as previously indicated:

. FIGS. 16a to 16g schematically represent successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to FIGS. 14a to 14g, in the case where the individual relates to the 'back of his body a fraudulent dielectric element,. FIGS. 17a to 17g schematically represent successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to FIGS. 14a to 14g, in the case where the individual relates to the 'front of his body and on his left side, a fraudulent dielectric element, and. FIGS. 18a to 18g schematically represent the successive stages of progression of an individual in the channel and the corresponding detection matrices on the microwave receiver transducers, similar to FIGS. 14a to 14g, in the case where the individual relates to the front of his body and on his right side, a fraudulent dielectric element.

A comparative examination of the chronology of the state of the signals between FIGS. 14, 15, 16, 17 and 18 makes it possible to detect the presence of object X and its location on the body of the individual.

The analysis means 40 exploit not only the chronology of evolution of the signals on the same receiver transducer 210 or 220, but also the asymmetries between the signals received on the receiver transducers 210 or 220 front and respectively rear, as well as the asymmetries between the signals received on the right and left receiver transducers 210 or 220 respectively.

Of course, the number of sequences taken into account, here 7, is not limiting and must be adapted as a function of the relative dimensions of the channel, of the section of the individual and of the desired detection resolution.

Furthermore, the reference matrices used to detect the presence of object X must be multiplied to take into account all of the possible positions of the object on the individual (on the front, on the back or laterally) based on the operating principles (direct transmission, reflection, double echo) described with reference to Figures 4 to 11.

In practice, several levels of transducers 210, 220 are provided vertically superimposed, for example 15 levels of transducers, and each transducer 210, 220 cooperates itself not only with the transducers of the same level, but also with the transducers of the lower level and higher level transducers. The presence of these different levels of vertically superimposed transducers makes it possible to know the vertical position of any dielectric object detected.

The analysis means thus have a large number of matrices of detection signals allowing a fine detection of the potential presence of a dielectric material delaying microwaves, on an individual, and allowing the localization of such a material. on the body of the individual, that is to say both his position in height on the body, but also his position on a horizontal section of the body.

It will be noted that the possibility has been mentioned, with reference to FIGS. 9 to 11, of receiving double echoes due to a reflection on the fraudulent substance X to be detected and to a reflection on the body of the individual I. However, depending on the configuration and / or the positioning of the fraudulent X objects to be detected, a receiving transducer 210 or 220 can if necessary receive more than 2 echoes as mentioned in particular in FIGS. 17c, 17e, 18c and 18e, or even echoes expanded.

Preferably, in the context of the invention, the means 300 are adapted to carry out at least one of the following steps and preferably the combination of all of the following steps:

measurement of the delay and of the amplitude of a direct microwave transmission between each pair of transmitters 210Tx, 220TX and receiver 210Rx, 220Rx coaxial located on the two opposite columns 10, 20,

- measurement of the delay and the amplitude of an oblique microwave transmission between each transmitter 210Tx, 220TX located on a column 10, 20 and the receivers 210Rx, 220Rx which surround the receiver located on the opposite column coaxial of the transmitter,

- measurement of the delay and the amplitude of the microwave wave emitted by each transmitter transducer 210Tx, 220TX and reflected towards the same transducer forming a receiver 210Rx, 220Rx or towards the receivers 210Rx, 220Rx framing the latter, by the body d '' an individual or by a fraudulent (non-metallic) substance carried by this individual,

- detection of the presence of a double echo of microwave waves reflected by a fraudulent substance and by the body of an individual,

- comparison of microwave waves transmitted directly with a reference value of transmission in a vacuum and transmission of an alarm in the event of detection of a delay greater than a threshold and with an amplitude corresponding to a range of substances which delays and attenuates microwave,

- comparison of the microwave waves transmitted directly with microwaves transmitted on adjacent transducers and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals (comparable to the presence of a non-metallic and non-metallic substance) permeable to microwaves),

- comparison of the oblique microwave waves with a reference value in a vacuum and generation of an alarm in the event of detection of delay greater than a threshold and with an amplitude corresponding to a predetermined range representative of substances which delay and attenuate the microphones -ondes,

- comparison of the microwave waves transmitted obliquely with the microwave waves transmitted directly adjacent and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals (comparable to the presence of a non-metallic substance and not permeable to microwaves),

- comparison of a double echo detected with transmission values in a vacuum and generation of an alarm in the event of detection of a delay greater than a threshold between the peaks of the two echoes with an amplitude greater than a threshold (representative of '' a substance which reflects part of the wave (first echo) and which delays and attenuates the non-reflected signal (second echo)),

measurement of the height of the body of an individual passing through the channel 30 which corresponds to a microwave wave reflection, preferably at each column,

- determine the position of an individual passing through the channel, between the inlet and the outlet of the channel, by analyzing the signals from the microwave receiver transducers,

- measurement of changes in inductive fields due to metallic substances carried by an individual passing through the channel,

- display of the height and the right or left side of the channel on which a metallic object and a dielectric object are detected in correlation,

- display of the front and rear type silhouette of the individual passing through the canal, sized in size on the basis of a measurement carried out by detection of reflection of microwave beams with positioning and indication of the nature of metallic objects and non-metallic dielectric objects detected,

- generation of inductive metal detector fields in the frequency range between 70Hz and 30kHz,

- generation of microwave beams in the range between 10 GHz and 90 GHz.

The device according to the present invention which has just been described can be supplemented by auxiliary equipment, for example by means of sampling and analysis of substances, vapor or traces of particles and / or by means of analysis nuclear magnetic resonance type, complex impedance analysis means and / or radioactive radiation detector means.

Such means are known per se in their general structure and will therefore not be described in more detail below.

Of course, the present invention is not limited to the embodiments previously described, but extends to all variants in accordance with its spirit.

Thanks to the detection of spatial correlation existing between metallic objects and the dielectric materials detected, the present invention allows in particular a reliable detection of explosives carried by individuals, for example belts of explosives, in particular comprising in combination of small objects. metal. It also allows reliable detection of the content of cases carried by individuals since the invention allows reliable detection over the entire height of the columns, up to the ground.

Claims (20)

1. Device intended for the detection of unauthorized objects or materials carried by an individual in a zone with protected access, characterized in that it comprises: - at least two columns (10, 20) defining between them a channel (30) through which individuals to be controlled can pass, - windings (110, 120) distributed in the two columns (10, 20), adapted to emit a magnetic detection field and adapted to detect disturbances of the magnetic detection field induced during the passage of an individual through the channel between the two columns, - microwave transmitter / receiver means (210, 220) arranged in the two columns (10, 20), and analysis means (40) adapted to analyze the signals from the receiver coils (110, 120) to detect the presence of metallic object carried by an individual passing through said channel formed between the two columns (10, 20), to analyze signals from microwave receivers (210Rx, 220Rx) corresponding to the signals transmitted from a column to the opposite column and to the signals reflected from a column to this same column to detect the presence of dielectric material carried by the individual passing through said channel and to establish the spatial correlations existing between the metallic objects and the dielectric materials detected. 2. Device according to claim 1, characterized in that the analysis means (40) proceed by analyzing the delay and the amplitude of the signals received with respect to a reference. 3. Device according to one of claims 1 or 2, characterized in that the analysis means (40) proceed by comparison of the signals received on a receiver with reference signals representative of the transmission in a vacuum and / or of reflection on a body. 4. Device according to one of claims 1 to 3, characterized in that the analysis means (40) generate an alarm in the event of detection of a deviation greater than a threshold between the received signals and a reference. 5. Device according to one of claims 1 to 4, characterized in that the means (210, 220) microwave transmitters / receivers comprise several microwave transducers distributed vertically on each column (10, 20). 6. Device according to claim 5, characterized in that the vertical distance between two adjacent microwave transmitters / receivers (210, 220) is between 2 and 10cm. 7. Device according to one of claims 1 to 6, characterized in that the microwave transducers (210, 220) operate in a frequency range between 5 and 90GHz, advantageously between 10 GHz and 30G and very preferably between 12 and 20GHz. 8. Device according to one of claims 1 to 7, characterized in that the various microwave transducers (210, 220) located on a column (10) are located respectively coaxially with a transducer located opposite the column ( 20) opposite. 9. Device according to one of claims 1 to 8, characterized in that each microwave transducer (210, 220) is adapted to work alternately in transmitter or receiver or in transmitter and receiver. 10. Device according to one of claims 1 to 9, characterized in that each microwave transmitter (210Tx, 220Tx) is adapted to transmit towards a microwave receiver (210Rx, 220Rx) coaxial on the column opposite, as well as in the direction of the transducers adjacent to this opposite coaxial transducer. 11. Device according to one of claims 1 to 10, characterized in that each receiver (210Rx, 220Rx) is adapted to receive from a coaxial transmitter (210Tx, 220Tx) located on the opposite column, as well as from the transducers adjacent to this opposite coaxial emitting transducer. 12. Device according to one of claims 1 to 11, characterized in that the analysis means (40) are adapted to operate at least one of the following functions: - measurement of the delay and the amplitude of a direct microwave transmission between each pair of coaxial transmitters (210Tx, 220TX) and receiver (210Rx, 220Rx) located on the two opposite columns (10, 20), - measurement of the delay and the amplitude of an oblique microwave transmission between each transmitter (210Tx, 220TX) located on a column (10, 20) and the receivers (210Rx, 220Rx) which frame the receiver located on the opposite coaxial column of the transmitter, - measurement of the delay and the amplitude of the microwave wave emitted by each transmitting transducer (210Tx, 220TX) and reflected towards the same transducer forming the receiver (210Rx, 220Rx) or towards the receivers (210Rx, 220Rx) framing this last, by the body of an individual or by a fraudulent substance carried by this individual, - detection of the presence of a double echo of microwave waves reflected by a fraudulent substance and by the body of an individual, - comparison of microwave waves transmitted directly with a reference value of transmission in a vacuum and transmission of an alarm in the event of detection of a delay greater than a threshold and with an amplitude corresponding to a range of substances which delays and attenuates microwave, - comparison of the microwave waves transmitted directly with microwaves transmitted on adjacent transducers and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals, - comparison of the oblique microwave waves with a reference value in a vacuum and generation of an alarm in the event of detection of delay greater than a threshold and with an amplitude corresponding to a predetermined range representative of substances which delay and attenuate the microphones -ondes, - comparison of the microwave waves transmitted obliquely with the microwave waves transmitted directly adjacent and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals, - comparison of a double echo detected with transmission values in a vacuum and generation of an alarm in the event of detection of a delay greater than a threshold between the peaks of the two echoes with an amplitude greater than a threshold - analysis of the chronology of evolution of the signals on the same receiver transducer (210, 220), of asymmetries between the signals received on front and respectively rear receiver transducers, as well as of asymmetries between the signals received on right and left receiver transducers (210, 220) respectively. 13. Device according to one of claims 1 to 12, characterized in that the analysis means (40) are adapted to operate at least one of the following functions: - measurement of the height of the body of an individual passing through the channel (30) which corresponds to a microwave wave reflection, preferably at each column, - determine the position of an individual passing through the channel, between the inlet and the outlet of the channel, by analyzing the signals from the microwave receiver transducers, - measurement of changes in inductive fields due to metallic substances carried by an individual passing through the channel, - display of the height and the right or left side of the channel on which a metallic object and a dielectric object are detected in correlation, - display of the front and rear type silhouette of the individual passing through the canal, sized in size on the basis of a measurement carried out by detection of reflection of microwave beams with positioning and indication of the nature of metallic objects and non-metallic dielectric objects detected. 14. Device according to one of claims 1 to 13, characterized in that the coils (110, 120) distributed in the two columns (10, 20), adapted to emit a magnetic detection field and adapted to detect disturbances of the detection magnetic field induced during the passage of an individual through the channel between the two columns generate inductive fields in the frequency range between 70Hz and 30kHz. 15. Device according to one of claims 1 to 14, characterized in that the height of the columns (10, 20) is between 150 and 200cm, advantageously between 150 and 180cm. 16. Device according to one of claims 1 to 15, characterized in that it comprises a vertical series of microwave transducers (210, 220) superimposed vertically on each column (10, 20). 17. Device according to one of claims 1 to 15, characterized in that it comprises two vertical series of microwave transducers (210, 220) superimposed vertically on each column (10, 20). 18. Device according to claim 17, characterized in that the horizontal distance between two transducers (210, 220) located in the same column is between 10 and 30cm. 19. Method for detecting unauthorized objects or materials carried by an individual in a protected access area, characterized in that it comprises the steps which consist in analyzing the signals from the receiver coils (110, 120) to detect the presence of metallic object carried by an individual passing through said channel formed between the two columns (10, 20), analyzing signals from microwave receivers (210Rx, 220Rx) corresponding to the signals transmitted from a column up to to the opposite column and to the signals reflected from a column to this same column to detect the presence of dielectric material carried by the individual passing through said channel and to establish the spatial correlations existing between the metallic objects and the dielectric materials detected . 20. Method according to claim 19, characterized in that it implements at least one of the following steps and preferably a combination of the following steps: - measurement of the delay and the amplitude of a direct microwave transmission between each pair of coaxial transmitters (210Tx, 220TX) and receiver (210Rx, 220Rx) located on the two opposite columns (10, 20), - measurement of the delay and the amplitude of an oblique microwave transmission between each transmitter (210Tx, 220TX) located on a column (10, 20) and the receivers (210Rx, 220Rx) which frame the receiver located on the opposite coaxial column of the transmitter, - measurement of the delay and the amplitude of the microwave wave emitted by each transmitting transducer (210Tx, 220TX) and reflected towards the same transducer forming the receiver (210Rx, 220Rx) or towards the receivers (210Rx, 220Rx) framing this last, by the body of an individual or by a fraudulent substance carried by this individual, - detection of the presence of a double echo of microwave waves reflected by a fraudulent substance and by the body of an individual, - comparison of microwave waves transmitted directly with a reference value of transmission in a vacuum and transmission of an alarm in the event of detection of a delay greater than a threshold and with an amplitude corresponding to a range of substances which delays and attenuates microwave, - comparison of the microwave waves transmitted directly with microwaves transmitted on adjacent transducers and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals, - comparison of the oblique microwave waves with a reference value in a vacuum and generation of an alarm in the event of detection of delay greater than a threshold and with an amplitude corresponding to a predetermined range representative of substances which delay and attenuate the microphones -ondes, - comparison of the microwave waves transmitted obliquely with the microwave waves transmitted directly adjacent and generation of an alarm in the event of a deviation greater than a threshold detected between the different signals, - comparison of a double echo detected with transmission values in a vacuum and generation of an alarm in the event of detection of a delay greater than a threshold between the peaks of the two echoes with an amplitude greater than a threshold, - analysis of the chronology of evolution of the signals on the same receiver transducer (210, 220), of asymmetries between the signals received on front and respectively rear receiver transducers, as well as of asymmetries between the signals received on receiver transducers (210, 220) right and respectively left, - measurement of the height of the body of an individual passing through the channel (30) which corresponds to a microwave wave reflection, preferably at each column, - determine the position of an individual passing through the channel, between the inlet and the outlet of the channel, by analyzing the signals from the microwave receiver transducers, - measurement of changes in inductive fields due to metallic substances carried by an individual passing through the channel, - display of the height and the right or left side of the channel on which a metallic object and a dielectric object are detected in correlation, - display of the front and rear type silhouette of the individual passing through the canal, sized in size on the basis of a measurement carried out by detection of reflection of microwave beams with positioning and indication of the nature of metallic objects and non-metallic dielectric objects detected.